Self-purging lubricant reservoir

ABSTRACT

In a preferred embodiment, the axle bearing caps of a railway locomotive traction motor include oil containing sumps from which lubricating oil is delivered by wick means to lubricate the axlecarrier motor support bearings. Overflow conduit means are provided which connect with an interior portion near the bottom of the sump and extend upwardly to an overflow outlet that is open to atmosphere and located at approximately the desired maximum oil level in the sump. When oil is added to the sump in excess of that required to reach the maximum level, the excess volume is forced from the bottom of the sump, out through the overflow conduit, thereby removing water and other contaminating liquids which are heavier than oil and settle to the bottom of the sump.

Unite States Patet 51 May to, 1972 Peterson [54] SELF-P GING LUBRICANTRESERVOIR [72] Inventor: David W. Peterson, Oak Brook, 1]].

[73] Assignee: General Motors Corporation, Detroit,

Mich.

[22] Filed: Aug. 27, 1970 [21] App]. No.: 67,513

[52] U.S.Cl. ..l84/103 12,210/532 [51] Int. Cl .B01d 17/02, FOlm 11/12[58] Field of Search ..210/532, 533; 184/103 R [56] References CitedUNITED STATES PATENTS Primary ExaminerManuel A. Antonakas Attorney-J. L.Carpenter and Robert J. Outland [5 7] ABSTRACT In a preferredembodiment, the axle bearing caps of a railway locomotive traction motorinclude oil containing sumps from which lubricating oil is delivered bywick means to lubricate the axle-carrier motor support bearings.Overflow conduit means are provided which connect with an interiorportion near the bottom of the sump and extend upwardly to an overflowoutlet that is open to atmosphere and located at approximately thedesired maximum oil level in the sump. When oil is added to the sump inexcess of that required to reach the maximum level, the excess volume isforced from the bottom of the sump, out through the overflow conduit,thereby removing water and other contaminating liquids which are heavierthan oil and settle to the bottom of the sump.

1 Claim, 7 Drawing Figures PATENTEUmnsm 3.6621358 SHEET 1 OF 2 sic B Yfia V/Q) i llfi ersan ATTORNFY PATENTEDMAY I6 SHHZT 2 OF 2 INVENTOR.

[([Hzerwn ATTORNEY SELF-PURGING LUBRICANT RESERVOIR BACKGROUND OF THEINVENTION This invention relates to self-purging lubricant reservoirsand, more particularly, to reservoirs having means for removingheavier-than-oil liquid contaminants through an overflow system. In itsmore particular aspects, the invention relates to oil retaining axlebearing caps for railway vehicle traction motors and like applicationswherein there is substantial exposure to the possibility ofcontamination of an oil reservoir by the entry of water during normaluse.

It is known in a railway locomotive to provide electric traction motorsmounted in the trucks and having one side thereof supported by axlebearings carried on the axle of the associated pair of drive wheels. Tolubricate the axle bearings, it is known to provide removable axlebearing caps, each of which contains a covered oil reservoir or sump andwick means for drawing the oil from the reservoir to the axle journals.Filler opening means are commonly provided and may be located atapproximately the desired maximum oil level in the sump to preventoverfilling. Separate overflow means may also be provided or the fillermeans may act as an overflow to maintain the maximum oil level, shouldthere by any additional volume of fluid added by external leakage ofcontaminants, such as water. A drain plug is normally provided fordraining contaminants from the system or for removing and changing thelubricant, if desired.

Since the traction motor bearing axle caps are located underneath thelocomotive in positions exposed to the weather, there is a substantialproblem of contamination by water seepage into the bearing capreservoirs. This occurs due to operation in rain and snow, as well asfrom locomotive washing operations wherein high pressure water jets maybe used to clean dirt from the locomotive and its running gear. Periodicmaintenance procedures for the axle bearing caps thus require not onlythat additional oil be added from time to time to make up for that usedin lubricating the bearings, but also that accumulated water beoccasionally drained by removal of the drain plug. If the latter step isoverlooked for an extended period, there is danger that accumulatedwater may rise high enough in the sump to contaminate the wick andstarve the bearings for oil. Since water settles to the bottom of thereservoir, the fact of its presence in the oil sump is not noticeableduring servicing if this is limited merely to adding oil through thefiller openings.

SUMMARY OF THE INVENTION The present invention provides overflow meansfor purging water and other heavier-than-oil liquid contaminants from anoil sump during the routine operation of filling the sump with oil. Asapplied to a locomotive traction motor axle bearing cap, the overflowmeans comprises a conduit which connects a point adjacent the interiorbottom of the oil sump with an overflow outlet open to atmosphere andlocated at a level approximately equal to the desired maximum oil levelin the sump. Such an overflow arrangement, which may take many physicalforms, operates, when the oil sump is filled above its maximum level, todrain liquid from the bottom of the sump, thereby draining off any wateror other heavy liquid contaminants which have settled to the bottom. Inthis way, the removal of contaminating water may be accomplished duringthe step of replenishing the oil level in the axle bearing reservoir bymerely adding oil until all the water is removed from the bottom of thesump and oil is seen to flow from the overflow conduit.

These and other advantages of the present invention will be more clearlyunderstood from the following description of several alternativeembodiments of the invention, taken together with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a pictorial view showing a railway locomotive traction motoras secured to its associated drive wheels and including traction motorsupport bearing axle caps having oil reservoir overflow means accordingto the present invention;

FIG. 2 is a cross-sectional view taken in the plane indicated by theline 2-2 of FIG. 1 and showing the interior detail of one of the axlecaps;

FIG. 3 is a cross-sectional view of the overflow conduit means utilizedin the embodiment of FIGS. l and 2;

FIG. 4 is a cross-sectional view of an axle cap arrangement utilizing analternative embodiment of overflow conduit means;

FIG. 5 is a partial cross-sectional view of an axle cap utilizing yetanother alternative embodiment of overflow conduit means;

FIG. 6 is a cross-sectional view of an axle cap arrangement utilizingstill another embodiment of overflow conduit according to the invention;and

FIG. 7 is a cross-sectional view of the overflow conduit arrangement ofthe embodiment of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1-3 ofthe drawings, numeral 10 generally indicates an electric traction motorfor a railway locomotive. Traction motor 10 is drivingly connectedthrough gears, not shown, to an axle 12 on the ends of which are secureda pair of flanged driving wheels 14. Drive wheels 14 and axle l2'alsosupport one side of the traction motor 10 by means of plain bearings 16which are secured around the axle by the traction motor frame 18 and apair of axle bearing caps 20, secured to the frame 18 by means of bolts22.

As best shown in FIG. 2, bearing caps 20 include an enlarged oil sump 24which is closed by a cover 26 and is adapted to contain a body oflubricating oil 28 having a predetermined desired maximum level. Cover26 supports, by means of a bracket 30, a wick 32 which may be made offelt or other suitable material. Wick 32 is supported with one endextending into the body of oil 28 and the other end engaging the journalsurface 34 of axle 12 so that oil is drawn by capillary action upthrough the wick and deposited on the axle journal. An opening 36 isprovided in the traction motor support hearing 16 to permit the wick 32to extend therethrough.

Each axle bearing cap 20 is also provided with a filler opening 38closed by a dust cap 40 and located in a side wall of the sump. A drainopening 42 is also provided in the bottom wall of the sump.

In accordance with the present invention, each axle cap 20 is alsoprovided with an overflow conduit assembly 44 best shown in FIG. 3.Conduit assembly 44 comprises a threaded plug 46 having a centralopening 48 in which is secured a standpipe 50. A second standpipe 52 isalso secured to the plug 46 and concentrically disposed in spacedrelation around standpipe 50, extending axially beyond standpipe 50 fora substantial distance. An inlet opening 54 is provided in the standpipe52 at a point near its connection with the threaded plug 46.

Conduit assembly 44 is adapted to be received within the sump drainopening 42, with plug 46 threadably secured within the opening 42 sothat standpipes 50, 52 extend vertically upwardly within the sump. Withthis arrangement, when oil is added to the sump through filler openings38, the oil level reaches a maximum height equal to the height of theinner standpipe 50, the oil flowing through the inlet opening 54 andbetween the standpipes up to the inner standpipe level. When additionaloil is added to the reservoir, the excess flows over the top ofstandpipe 50 and drains therethrough out through the central opening 48in the threaded plug 46. If there is any water in the sump at this time,it will have settled to the bottom, since it is heavier than oil andwill enter the inlet opening 54 and be forced out through the overflowconduit 44 in the manner just described. The extended height of theouter standpipe 52 prevents the draining of oil from the top of the sumpand requires the outlet flow to pass through opening 54 at the bottom ofthe standpipe 52.

Referring now to FIG. 4 of the drawings, there is shown an alternativeembodiment of axle bearing cap arrangement which is similar to that justdescribed, differing only in the type of overflow conduit meansutilized. In this embodiment, an outlet opening 56 is provided in asidewall of the bearing cap 20 at a point near and slightly below thefiller opening 38. An overflow tube 58 extends downwardly throughopening 56, having its open lower end adjacent the bottom of the oilsump 24. The upper end of the tube 56 is bent so that the opening facesdownwardly to reduce the possibility of water being splashed into thetube and entering the sump 24 in this manner.

In FIG. of the drawings, another embodiment of overflow conduit meansaccording to the invention is disclosed. In this embodiment the drainopening 42 of the bearing cap sump is fitted with a plug 60 having adownwardly extending fitting portion 62. Secured to the fitting portion62 by means of a clamp 64 is one end of a formed hose 66 which extendsupwardly, externally of the oil sump, to a point approximating thedesired maximum oil level within the sump. The upper end of the hose isbent so that it opens downwardly to reduce the possibility of waterentering the sump through the hose.

ln FIGS. 6 and 7 still another embodiment of overflow means according tothe invention is disclosed. As shown in FIG. 6, bearing cap 20 isprovided with an alternative filler opening 68 located in the cover 26and closed by the usual dust cap 40. In this arrangement, the normalfiller opening 38 is replaced by an outlet opening 70 which is disposedan overflow conduit assembly 72 of the type shown in FIG. 7. Assembly 72comprises a straight tube 74 supporting a threaded bushing 76 and a cap78. A plurality of circumferentially spaced outlet holes 80 are providednear one end of the tube, the holes being shielded by the cap 78 whichis open axially of the tube in a downwardly facing direction, asinstalled. Conduit assembly 72 is installed within opening 70 with thethreaded bushing fixed within the opening so that tube 74 extendsinteriorly of the sump, having its open bottom adjacent the bottom ofthe sump. Openings 80 are located exteriorly of the sump and areprotected by the cap 78 so as to prevent the splash of water into thetube assembly.

Operation of the embodiments of FIGS. 4-7 is substantially identical, inthat filling of a sump with oil above the level of the upper end of itsoverflow conduit causes fluid in the bottom of the sump to flow outthrough the conduit. In this way, water collecting in the bottom of thesump is purged and a desired maximum oil level is maintained.

The above-described embodiments are intended to be illustrative only andare not meant to limit the scope of the invention as defined in thefollowing claims.

Iclaim:

1. An oil retaining bearing cap for a railway vehicle drive motor havingan oil lubricated axle bearing, said bearing cap comprising a coveredsump for retaining therein a supply of oil,

a filler opening above the normal oil level for adding oil to said sump,said filler opening being provided with an openable cover,

an overflow conduit associated with said bearing cap and having upperand lower ends and an impervious wall intermediate said ends, said upperend having an overflow outlet at approximately the desired level of oilin said sump, said outlet being open to atmosphere and connecting withthe exterior of said sump, and said lower end being open to a lowerportion of said sump adjacent the bottom thereof to receive fluids fromsaid sump lower portion,

a drain opening in the bottom of said sump, said overflow conduitcomprising a pair of standpipes secured around said drain opening inconcentric spaced relation within said sump, the inner one of saidstandpipes being sealed around said opening and extending upwardly tothe desired maximum or level and the outer one of said standpipes havingan opening adjacent its bottom end and extending upwardly to a levelabove the inner standpipe, whereby the addition of an excessive volumeof fluid to said sump will cause a volume of fluid to be forced from thelower portion of said sump into said overflow conduit and out throughsaid overflow outlet, thereby selectively removing from the sump waterwhich may have settled to the bottom thereof while maintaining thedesired maximum oil level in said sump, said standpipes being bothsecured to a threaded plug to form an assembly removable from saidbearing cap to permit complete draining of the sump.

1. An oil retaining bearing cap for a railway vehicle drive motor havingan oil lubricated axle bearing, said bearing cap comprising a coveredsump for retaining therein a supply of oil, a filler opening above thenormal oil level for adding oil to said sump, said filler opening beingprovided with an openable cover, an overflow conduit associated withsaid bearing cap and having upper and lower ends and an impervious wallintermediate said ends, said upper end having an overflow outlet atapproximately the desired level of oil in said sump, said outlet beingopen to atmosphere and connecting with the exterior of said sump, andsaid lower end being open to a lower portion of said sump adjacent thebottom thereof to receive fluids from said sump lower portion, a drainopening in the bottom of said sump, said overflow conduit comprising apair of standpipes secured around said drain opening in concentricspaced relation within said sump, the inner one of said standpipes beingsealed around said opening and extending upwardly to the desired maximumoil level and the outer one of said standpipes having an openingadjacent its bottom end and extending upwardly to a level above theinner standpipe, whereby the addition of an excessive volume of fluid tosaid sump will cause a volume of fluid to be forced from the lowerportion of said sump into said overflow conduit and out through saidoverflow outlet, thereby selectively removing from the sump water whichmay have settled to the bottom thereof while maintaining the desiredmaximum oil level in said sump, said standpipes being both secured to athreaded plug to form an assembly removable from said bearing cap topermit complete draining of the sump.